confused about tyre size - help!

[bongo&4kids]

Hello fellow Bongo owners!
I just picked up my new Bongo 4WD last week after much searching and looking into all things Bongo, mainly because my wife and I are expecting our 4th child this summer and we needed more seats! + my dad had a camper when I was young, so I have fond memories of camping, trips the beach, and days out with the back loaded up with football, frizbee, cricket set, picnic, folding table, bucket and spade, etc etc!

I am a bit confused though about the correct / recommended tyre sizes and pressures, and hoping someone could offer the right advice?

When I bought the vehicle last week it still had winter tyres fitted, which the previous owner had fitted for a skiing trip. I have the invoice in the documents that he gave me and they are 2 different sizes, which seem to match the specifications:
195/70R15 INFINITY WINTER and 215/65HR15 JINYU WINTER

However, after I got the tyres swapped over to the summer tyres this week (included when purchased the vehicle), I have just realised that the sizes on the summer tyres seem to be the same for front and rear- Fronts, 215/65R15 100H (ACELERA) and Rear, 215/65R15 96H (MAXXIS).

I am assuming that the summer tyres were put on before the previous owner bought the Bongo (he had it less than a year), so it seems that the garage he went to for the winter tyres got it right, and someone before that just put the same sizes on all wheels.

I have read that getting the sizes correct is important otherwise it can affect the 4WD?

Should I now be trying to get smaller tyres for the front?

[g8dhe]

That's the normal in this country, otherwise you spare will only fit half the vehicle!
I would guess that most people run the same tyre size all round, you need the wider tyres for the rear to put the power down onto the road, but the smaller width tyres for the front only marginally make the steering lighter, so everybody sticks to the same all round.

[bongo&4kids]

Thanks, that's great.

What about the tyre pressures? should they also be the same for all tyres, if the fronts are also fitted with 215s?

[g8dhe]

Depends more on how your loaded, normal is less in the front than at the rear, with our full side conversion and normally heavily loaded up we run 38-40 PSI rear and 36-38 PSI front.

[bongo&4kids]

Thanks Geoff for help, awesome.

[Bob]

Agree with Geoff, we have 215s all round and run 38 front 40 rear.

[bongo&4kids]

I took the Bongo out today for a drive for the first time after getting the tyres changed over from winter to summer.

The steering wheel definitely feels lighter and less responsive, particularly when turning steering wheel to the right. But when I straighten the steering wheel up the vehicle is veering over to the left. Driving feels much less stable.

Does anyone know if this might be due to the fact that the fronts have now changed from the smaller size to the larger size, and affected the balance? Should I go back to the garage and ask for wheel alighnment?

thanks!

[Bob]

I've never noticed any difference swapping winter/summer tyres.

Starting with basics have you checked tyre pressures?

Just swapping wheels is very unlikely to affect tracking and balance would give vibration at a certain speed.

[Northern Bongolow]

if all the tyres are the same size and pressures and tyre make its possible it would benefit from all 4 wheels aligning with a laser. this makes sure all the wheels are travelling in the same direction at the same speed.

ive run 4 same size summer, and a different sized set of 4 winter for 5 years and had no problems at all.

but.

have you got a rear limited slip differential.?

your winter tyres were the correct factory spec, this is the rears have bias, the fronts are 70% of 195 =. the rears are 65% of 205 or 215 = . if you do the above sums you will find that the rears are within a couple of % larger than the fronts, this makes the bongo mainly rear wheel drive until a wheel slip is detected then is gives drive to the front end via a viscus coupling, this coupling locks the drive front to rear when the rears slip, occasionally if your viscus coupling is a really good one the drive can feel wooley or a little odd as the viscus coupling is struggling to work out what wheel is travelling further whilst its in a turn arc, in a turn the front obviously have to travel furthest, then on a right turn the rear left travels next furthest, then the right rear the least travel, result a confused viscus.

just re read your original post, noticed your summer tyres are mixed make front to back, this could give you problems, even if the same size, i bet if you measured round with a tape they would have a different circumference measurement. are the maxis worn down and the acceleras newish. if yes try swapping them round, i would run the higher weight tyres (100) on the rear, and the lighter (96 ) on the front, see if that improves owt.

[bongo&4kids]

How would I find out if my Bongo has a rear slip differential? - thanks!

[Northern Bongolow]

jack both rear wheels up clear of the ground, spin one wheel by hand quite hard, if its a standard diff the opposite wheel will spin in the reverse direction , if its a limited slip rear diff the opposite rear wheel will spin in the same direction, or look on the russian web site that someone may post a link too, put in your vin number and that will give you a limited build spec that it left the factory with, this includes engine gearbox and diff spec as well as trim and paint colours etc.

[teenmal]

Hello fellow Bongo owners!
I just picked up my new Bongo 4WD last week after much searching and looking into all things Bongo, mainly because my wife and I are expecting our 4th child this summer and we needed more seats! + my dad had a camper when I was young, so I have fond memories of camping, trips the beach, and days out with the back loaded up with football, frizbee, cricket set, picnic, folding table, bucket and spade, etc etc!

I am a bit confused though about the correct / recommended tyre sizes and pressures, and hoping someone could offer the right advice?

When I bought the vehicle last week it still had winter tyres fitted, which the previous owner had fitted for a skiing trip. I have the invoice in the documents that he gave me and they are 2 different sizes, which seem to match the specifications:
195/70R15 INFINITY WINTER and 215/65HR15 JINYU WINTER

However, after I got the tyres swapped over to the summer tyres this week (included when purchased the vehicle), I have just realised that the sizes on the summer tyres seem to be the same for front and rear- Fronts, 215/65R15 100H (ACELERA) and Rear, 215/65R15 96H (MAXXIS).

I am assuming that the summer tyres were put on before the previous owner bought the Bongo (he had it less than a year), so it seems that the garage he went to for the winter tyres got it right, and someone before that just put the same sizes on all wheels.

I have read that getting the sizes correct is important otherwise it can affect the 4WD?

Should I now be trying to get smaller tyres for the front?

Have a look for a plate/label on the drivers door jam, this will give you the proper spec for your vehicle. Deviating from the Manufacturers specifications can cause handling problems and insurance implications.

[bongo&4kids]

ok, think I get it now. Its not the size necessarily that counts, e.g. 195 or 215, its the rolling circumference - this is what affects the 4WD if the tyres are mismatched? - one set of tyres are forced to spin more quickly than the other.

I will try to swap the fronts to rear, and see if this helps.

But if I left it the way it is now, would that cause the differential to fail? Is this a problem with Bongos?

[Northern Bongolow]

it sounds like you nearly have it mate,

go on here and type your old tyre size in and the new tyre size in then read along and see what the actual circumference difference is, it states that the recommended difference is just over 1 %, any more can do damage to a viscus coupling.

http://www.tyresave.co.uk/tyresize.html.

it isnt a problem with viscus coupling on a bongo, its just the limitations of this type of (4) wheel drive, the freelanders used to have this type among other so called 4 wheel drive cars etc.

running well worn tyres with new on the same axle or old and new front to back can play havoc with em, best to either do it by the book, ie 195 70 front and 205 or 215 rear or all new same size all round of the larger sizes and weight rate.(consider insurance angle though).

[bongo&4kids]

Took my Bongo back to the garage today. Done the rear wheel test for anti slip differential, and the other wheel turned in the opposite direction, so I understood that to mean that my Bongo does not have the limited slip differential.

But I did swap the tyres around from front to back, and got the wheel alignment done, and that seems to have sorted it out. Much smoother driving now!

Thanks everyone for your help and advice!!
Off to a family festival at the weekend!!!